The annual Invasive Species Week is taking place between the 15th and 21st May 2023, led by the GB Non-Native Species Secretariat (NNSS) with many organisations taking the opportunity to raise awareness of the issues and work that is being done to address invasive non-native species (INNS).
What are invasive non-native species (INNS)?
Non-native species (also known as alien species and non-indigenous species) are species which have arrived in a new location outside their natural range due to intentional or unintentional human actions. Most non-native species are harmless but around 10-15% spread and become invasive by harming wildlife and the environment. Limiting the spread of all non-native species limits the opportunities of one arriving which will establish and become an invasive non-native species.
Species that are highly adaptable or from similar environments pose the biggest threat of invading
How are they spread?
The routes used by non-native species to reach new locations are called pathways. These pathways can be intentional and unintentional and include: ballast water, hull fouling, contaminated equipment such as fishing kit, dive gear, kayaks and paddleboards, marine litter, escapees from sites where they are kept, releases to the wild such as unwanted pets, illegal introductions, deliberate releases to the wild by those believing it is a positive action, hitch hikers on aquaculture stock and live bait.
Why are they a problem?
As their name suggests, invaders generally cause problems and invasive non-native species have various tools at their disposal. An invasive non-native species can spread disease, prey on native species and their eggs, out-compete native species for food and habitat, damage environments, breed with native species, change ecosystems and damage equipment and structures such as waterways and pipes. They can push native species to extinction, and in Great Britain invasive non-native species (terrestrial, plant, aquatic) are estimated to cost the GB economy £1.84 billion per year.
All species have the potential to carry diseases, but some species also carry and spread diseases of international concern.
What is being done to prevent this?
There are a range of actions being taken to prevent the spread of invasive non-native species from international agreements such as the Ballast Water Management Convention to national legislation, eradication programmes, biosecurity guidance and awareness raising campaigns like Invasive Species Week.
Legislation has been implemented to control the use of non-native species. Controls on aquaculture ensure that potentially invasive species are only farmed in secure facilities such as indoor tanks and new species in the ornamental trade are limited to those least likely to establish in our waters.